Clinical and cytopathological characteristics of HTLV-1⁺ hodgkin lymphoma

Human T-lymphotropic virus-1 (HTLV-1)⁺ Hodgkin lymphoma (HL) is difficult to differentiate from adult T-cell leukemia/lymphoma (ATLL) with HL-like histology (HL-like ATLL).

Cytological and immunohistological features, HTLV-1 proviral DNA integration, and rearrangements of the T-cell receptor (TCR) Cβ1 gene were examined in 11 HTLV-1⁺ patients with HL-like disease.

Six patients were classified as HTLV-1⁺ HL and five as HL-like ATLL in accordance with genetic findings of HTLV-1 proviral DNA integration and rearrangements of the TCR Cβ1 gene. Small ordinary looking lymphocytes with round nuclei were detected in the background of six patients with HTLV-1⁺ HL, which were immunohistochemically negative for CD25 and CC chemokine receptor (CCR)4 and had a low MIB1 labeling index (mean: 28.3%). In the HL-like ATLL specimens, small- and medium-sized atypical lymphocytes with indented and irregular-shaped nuclei were found, and were diffusely positive for CD25 and CCR4, with high MIB1 labeling (mean: 76%). Both groups had scattered CD30⁺ and CD15⁺ Hodgkin and Reed Sternberg (RS) giant cells, with or without CD20 expression and Epstein-Barr virus infection. The 50% overall survival period was significantly longer for the HTLV-1⁺ HL group (180 months) than for the HL-like ATLL group (7.8 months; P = .004).

HTLV-1⁺ HL showed typical small lymphoid cells with a low MIB1 labeling index in a background of Hodgkin and RS cells, with some scattered CD25⁺ and CCR4⁺ lymphocytes. In HTLV-1 endemic areas, distinguishing HTLV-1⁺ HL from HL-like ATLL is important because of their differing treatment strategies and prognoses.